Someone in the comments section of this Temple of Schlock post suggests that the film was proposed as part of a series to be made by Gold Key Entertainment (the same as the comic books, I wonder?) but was never actually made. It has a listing on IMDb, but aside from three cast members (Price, Stephanie Beacham and Andrew Kier), no director, writer or crew is listed.

Here's a list of Gold Key's "Zodiac Features":

Curse of the Moonchild turns up in some old TV listings, but then the Oliver Reed title The Age of Pisces doesn't even show up on IMDb.

THE ARIES COMPUTER was never made. In 1972, Gold Key TV announced they were beginning production on a series of horror/sci-fi TV movies, each of which dealt with a sign of the zodiac. None of the films were made; but they still continue to pop up in filmographies, and some of them were ever offered in syndication for years, even though they didn't exist.

Weirdly, I just listened to a podcast about the career of Adam West yesterday (Gilbert Gottfried's Amazing Colossal Podcast) and they referred to another film he was supposed to have made in Italy, with Giancarlo Giannini, but it was never actually made either (I think someone doing research read an old Variety article announcing its production or something).